Aerosol contact cleaner can cure a wide variety of problems on a boat -- including connectors, switches, wiring harnesses, antenna connections, or fuse holders. Sometimes referred to as "tuner cleaners," a blast of this stuff dissolves and washes away dirt, oil, and grease, plus it evaporates quickly without leaving any residue. Be sure the one you choose won't harm plastics. The brand I have on my repair bench is CRC's QD Contact Cleaner ($6.50/11 oz.; www.crcindustries.com), which is specifically formulated for marine use.